Overtones is a new column by Jayson Greene that examines how certain sounds-- a snare crack, a synth blob, a ghostly string sample-- linger in our minds and lives.

If you were a gangsta rap fan who spoke no English, you might mistakenly believe that the genre has gotten strangely happy as of late. Lyrics remain rooted in the hard stuff-- chopping bricks, stacking drug money, building empires-- but within the production, a revolution is taking place. "Karate Chop", by the Atlanta singer/warbler Future, is one of the year's most omnipresent street singles, and the beat, by 19-year-old producer Metro Boomin', sounds as suited to Nicktoons as a subwoofer-stacked SUV. The low end blares, but above it, the hiccuping synth and neener-neener siren blow raspberries: If this is fight music, it's the BIFF-BANG-POW of the 1960s Batman TV show.

In Atlanta, the producers surrounding Future and his Free Bandz Gang have turned their search for brightly colored sounds into a kind of arms race as Future mutates his own voice into ever-odder shapes. Lex Luger, the Atlanta-via-Virginia producer whose crisply quantized ticking snares and massed minor-key horns have defined gangsta rap for the past few years, is a primary influence, but this time around, there's a distinctly Hanna Barbera feel to the proceedings. Luger’s huge, booming beats had a whiff of absurdity buried in them, and these instrumentals make it explicit: Metro Boomin' marks his tracks with a variation on the upward synth sweep Lex Luger uses to stamp his production, which you can hear rippling just before the beat drops on "Karate Chop". In his hands, it resembles nothing so much as the Scooby Doo bongo run sound.

But you don't have to stick to Future's music to hear this giddiness slowly crowding the frame; Chicago native Young Chop has perfected a sound with Chief Keef that is built out of a thousand squiggly, perpetual-motion earworms. Keef's entire persona is built upon joylessness-- he doesn't love getting drunk, he hates being sober-- and yet on "Diamonds", from last year's Finally Rich, Chop sends five or six different glistening synthesizers leaping and pinwheeling around each other behind him, each one tinny and tiny and folding into a swarming texture of other similar-sized noises. Build enough of these small interlocking elements up, and you get an assembly-line-gone-mad effect, an endless horizon of brightly colored pellets running in rows.

This is, by and large, is the current sound of street-level gangsta rap production-- it's like someone rescued the squealing baby from the bottom of Timbaland's "Are You That Somebody" beat and put him in front of an MPC. The reactions rappers have to this madness varies. Sometimes, they make a show of staying unmoved, like Keef, who wants no part of the beat's party. Other times, they join in on the fun: There's a song off Young Thug's recent 1017 Thug mixtape, for instance, named after the Pokémon character Pikachu, and the chorus goes: "My diamonds they say Pikachu/ They gon' wink at you." The beat around him, by Jaye Neutron, also says "Pikachu," the bright major-key synthesizers splitting the difference between bright crinkle and wet squelch, like sticky jelly on tinfoil. Young Thug isn't exactly a Pikachu figure-- he threatens to shoot you constantly. But within the larger canvas of the music, his voice is another brightly colored moving dot.

Rap fans might not like thinking of the music this way. Through all of its violent stylistic shifts, hip-hop has usually held onto the simple primacy of the voice. But as rap, electronic music, and ringtones have circled closer to one another over the years, the role of vocals in hip-hop has shifted and grown blurrier. Built on repurposed materials, the genre has always been swift at adapting to the demands of its medium. If New York City rap was tailor-made for underground dwellers familiar with a complicated, dense environment, and L.A. rap was for kids tooling around in cars with huge systems, the current wave meets the demands of its preferred medium: It sounds good enough to be enjoyed in a YouTube window playing in someone's bedroom.

The low-end still blares, but there's a distinctly Hanna Barbera
feel to the current sound of street-level gangsta rap production.

When I reach "Karate Chop" producer Metro Boomin' by phone, I tell him his beats often remind me of the dissolving platforms in Mega Man, or the pills thrown up by Dr. Mario. "I appreciate that," he says. "I came up playing the same games, and the thing about that music is that it was real simple, but intricate. I try to find sounds that are crazy and different to bounce off of the basic elements-- strings, keys, loud horns-- to set myself apart. I'm trying to stop somebody who’s listening-- rappers hear a lot of beats, you know?"

When I ask him who his influences are, Metro lists Shawty Redd, whose epic synth-based production gave Young Jeezy's first album it's heft, and his colleague Sonny Digital. But he singles out Atlanta-via-San Francisco producer Zaytoven most: "The thing I respect about Zay is that he sounds like nothing else," he says. "A lot of it’s similar, but it’s all got that certain bounce to it. It all sounds simple to people who don’t produce, but it’s not."

Zaytoven, aka Xavier Dotson, might be the pioneer of today's giggly wave of hip-hop beats. He's originally from San Francisco, another place where colorful rap production is the norm, but has lived in Atlanta for years, and is most known for working with Gucci Mane-- pick up any Gucci mixtape from the last five years, and he will have at least one beat on it. Like Metro, he works with an MPC, MIDI keys, and some minimal effects, building his beats one small, hooky layer at a time. Dotson's musical roots are in church-- he still plays organ-- but his rap production resembles the ice-cream truck rolling around outside of the cathedral more than anything happening inside it.

Dotson works fast and cheap, and he's incredibly productive (many of his beats are barely-retooled versions of themselves). A lot of his material is conveniently collected on the Zaytown mixtape series, which offer generous samplings of his beats for Gucci, JT the Bigga Figga, Shawty Lo, Future, and many others. He’s boiled his approach down to a science, and doesn’t mince words about it. "It usually takes me all of five minutes to make a beat," he tells me. Each beat is "10 or 12 sounds, including all the instruments and drums," and once he's determined the mix of sounds, the beat falls together like Tetris blocks. His approach is rinky-dink, but purposefully so, and he says it was a perfect suit for Gucci, in particular.

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"When we first started doing music together, his raps reminded me of nursery rhymes," says Zay. "Just the words he put together, the way he said them, it was something that a kid would want to say right back, because it's just so catchy and easy-sounding."

"People associate street music with hardness, but my key in making music was trying to give that trap sound a happy feel." -- Zaytoven

Zaytoven has some surprising idols of his own-- he frequently name-checks DJ Quik, a producer known for working with rich live instrumentation. “I came from the West Coast, and Quik’s music always stuck out to me more than Dr. Dre, or anybody else’s. I buy every single DJ Quik album, and on every single one there’s a song called ‘Quik’s Groove,’ and that’s where he’s just playing an instrument. It’s just a groove. There ain’t no rapping or nothing like that. I’m like, 'For a guy that makes street music, how do you make such quality music?'"

Zaytoven’s style might seem like the polar opposite of Quik’s. And yet there is a certain irrepressibility to Quik’s music that you can hear in Zay’s easy laugh, and in his beats. Quik’s productions, even when the lyrics detail harrowing personal demons, exude a carefree positivity. "I know all of the guys that I work with try to appeal to the streets and that's the way they want to come across, but at the same time, these guys are artists," Zaytoven continues. "When you look at them, they dress a certain way, their hair is cut a certain way, they color-coordinate in certain ways. When I'm around these guys, they joke a lot. They do a lot of different things that are colorful and put me in this music-making mind frame where it can be hard, but it’s still got to have some lightness to it." Zaytoven hears his influence in producers like Metro Boomin' and he’s happy about it. "It’s sort of their sound now," he says.

He continues: "People associate trap music or street music with hardness, but my key in making my music was trying to give a happy feel to that trap sound, just to make it more interesting and exciting. I'm just naturally a very happy person-- I try to make gloomy music, but it just don’t get that dark."